The usual suspects: fonts, video drivers, sounds drivers, various USB devices supports, sleep/wake issues.
And lack of basic apps, like a good multitabbed SSH/RDP terminal.
This comes up somewhat regularly, and probably always will - it’s the nature of the beast.
I’ve found myself very happy using a Mac as my main desktop. It’s not perfect either, but good enough.
Fedora is spectacular and has been spectacular for many years now. The driver support is brilliant. It was one of the first distros to have absolutely seamless integration with RAID mode NVME (which was something the XPS set it to).
I will be very surprised if you have to "tweak" your laptop. Everything that you have in OSX is already there - including nightmode, etc... the works.
And here's the cool part - customizing Fedora is a browser extension away! http://extensions.gnome.org/
It usually breaks for users, who do not respect package manager and what it does, break their installation with misc convenience scripts and tweaks run as root, and then wonder, what went wrong.
It's tempting to compare Linux with MacOS, but also (in my opinion) unfair. Apple appears to be making conscious decisions about what goes in their machines and not simply picking the cheapest components. I think Windows is closer to a fair comparison (they have to try and support everything out there) I have had no more hassle under Linux than I've had with Windows.
EDIT: Rather than downvoting, perhaps those who disagree with me could tell me why other companies aren't capable of "making conscious decisions about what goes in their machines"?
Apple is, after all, far from the only Unix vendor to do so. Whether it's HP-UX or Solaris, it's fairly common for Unix vendors to tightly couple their software to supported hardware. What is preventing Red Hat from offering a fully Red Hat compatible laptop that works near-perfectly out of the box?
If you do your purchase outside this list and something doesn't work, it was your decision and now your problem. It is not Redhat's or Canonical problem. They are not in hardware business, their partners are, and the information which models were tested and what was the result is publicly available.